Ma, A.; Lu, J., and Wang, T., 2012. Effects of elevation and vegetation on methane emissions from a freshwater estuarine wetland.

Methane (CH₄) emission rates from three different tidal elevations were measured in a freshwater wetland of the Yangtze River, China, estuary using a modified, static, closed-chamber technique. The intertidal zone covered by Phragmites australis is a source of atmospheric CH₄. The site at a higher elevation had lower CH₄ emissions than did a lower-elevation site (1.322 ± 1.15 mg m⁻² h⁻¹ vs. 11.66 ± 12.5 mg m⁻² h⁻¹). Methane emissions from the mudflats were negligible. Methane emissions showed remarkable seasonal variations, with the largest emissions occurring in summer and late-summer and the smallest emissions occurring in early spring. Although CH₄ emissions were related to soil temperature at depths of 5–10 cm, differences in CH₄ emissions among sites were mainly determined by the presence of P. australis. Simulatied experiments did not find significant differences in CH₄ fluxes between sites exposed to different submergence frequencies in the absence of plants, presumably because of substrate limitations. A higher tidal submergence frequency in the vegetated areas stimulated methanogenesis by enhancing vegetation photosynthesis and increasing the amount of plant litter submerged in water. The CH₄ flux rates from the clipped and unclipped sites differed significantly during the growing season. This highlights the importance of plants in the CH₄ flux, both as gas-transport conduits and through labile carbon production. The average net photosynthetic rate of P. australis at the lower elevation was higher (0.57 ± 0.2 gC m⁻² h⁻¹) than that at the higher elevation (0.43 ± 0.1 gC m⁻² h⁻¹), and more carbon was fixed and served as potential substrates for CH₄ production. The CH₄-C emissions played a minimal role in the carbon flux, which was about 0.3% for the higher-elevation site and 1.6% for the lower-elevation site. This suggests that high CH₄ emission rates in freshwater wetlands may be explained by higher plant photosynthetic carbon fixation.

Pu, R.; Bell, S.; Baggett, L.; Meyer, C., and Zhao, Y., 2012. Discrimination of seagrass species and cover classes with in situ hyperspectral data.

Seagrass habitats support a variety of ecosystem functions and an increasing interest has emerged for utilizing remote sensing to acquire information on the spatial extent and abundance of seagrass vegetation. Here we report on hyperspectral data collected from a combined laboratory and field-based study to examine the spectral qualities of seagrass species and evaluate whether seagrass species and levels of seagrass cover could be distinguished using true in situ hyperspectral data collected by a spectrometer overlying sea-grass-dominated vegetation in a shallow water setting in the central west coast of Florida. We also analyzed hyperspectral data measured in the lab to compare with those from in situ collections. Using a set of 97 field measurements we compared spectra qualities for different seagrass species, levels of seagrass cover, water depths, and substrate types over wavelengths 400–800 nm, using spectral data preprocessing and data transformation. Optimal wavelengths for identifying seagrass species and levels of seagrass cover were determined by two-sample t-tests. We also utilized principal component analysis (PCA) on spectra to evaluate if a set of first five PCs could be used to discriminate effectively among seagrass species and levels of seagrass cover. The experimental results indicate that the best accuracies for identifying species were produced with the data set of the second -derivative normalized spectra. The optimal wavelengths were 450, 500, 520, 550, 600, 620, 680, and 700 nm, most of which are related to the peaks of reflectance and absorption bands by photosynthetic and accessory pigments. A set of five optimal bands produced higher accuracies for identifying seagrass species (overall accuracy = 73% and average accuracy = 75%) compared with those from use of PCA. Data preprocessing techniques were demonstrated to be effective for improving discriminant accuracies of species and levels of seagrass cover.

Lapointe, B.E.; Herren, L.W., and Bedford, B.J., 2012. Effects of hurricanes, land use, and water management on nutrient and microbial pollution: St. Lucie Estuary, southeast Florida.

Multiple hurricanes impacted southeast Florida during 2004 and 2005, producing record rainfall and large-scale stormwater runoff into the urbanized St. Lucie Estuary (SLE). To assess effects on water quality, field samples were taken in June and November 2005 and March 2006 along the SLE's three main segments: the South Fork, connected via the C-44 canal to Lake Okeechobee; the North Fork, which receives residential and agricultural runoff from the C-23 and C-24 canals; and the Middle Estuary, which flows into the Indian River Lagoon and Atlantic Ocean. Salinities were <1‰ throughout the normally brackish estuary during the 2005 samplings, but returned to near-normal levels by March 2006 in all but the South Fork. Low salinities in 2005 correlated with low dissolved oxygen, high turbidity, elevated nitrogen and phosphorus concentrations, and high fecal and total coliform counts. Highest turbidity (84.4 NTU), nitrate (37.9 µM), and total dissolved nitrogen (130.8 µM) concentrations occurred in the South Fork, whereas the highest ammonium (15.4 µM), soluble reactive phosphorus (10.5 µM), and total dissolved phosphorus (13.8 µM) concentrations occurred in the North Fork. High fecal and total coliform counts occurred in tidal creeks adjacent to dense residential areas that rely on septic tanks for on-site sewage disposal. The data suggest that increased stormwater retention, minimization of freshwater releases from Lake Okeechobee, and enhanced treatment of both stormwater and sewage are needed to mitigate future stormwater-driven water quality perturbations in the SLE.

Peterson, C.; Minor, R.; Gates, E.B.; Vanderburgh, S., and Carlisle, K., 2012. Correlation of tephra marker beds in latest Pleistocene and Holocene fill of the submerged Lower Columbia River Valley, Washington and Oregon, U.S.A.

Seven tephra layers in the submerged fill of the Lower Columbia River Valley (LCRV) are radiocarbon dated (0.5–13 ka in age). They are correlated to reported eruption sources in the adjacent Cascade Range volcanic arc. The tephras provide a stratigraphic framework for the transgressive depositional filling of the tidal Columbia River system (∼200 km in length). The thickest and most continuous tephra marker beds in the LCRV are from the Mount Mazama set-O eruption at 7.7 ka. The eruption source for this tephra (1–10 m thick) is confirmed by glass geochemistry and radiocarbon dating of borehole samples from depths of −13 to −38 m (North American Vertical Datum of 1988 [NAVD88]). The Mazama set-O tephra conveniently divides the depositional sequences of the Early Holocene from the Late Holocene in the deep valley fill (50–120 m axial valley depth). A much deeper tephra, at −84 m, is attributed to Mount St. Helens set-S/J eruptions at ∼13 ka, which confirms the end of the Glacial Lake Missoula Flooding in the LCRV. Late Holocene tephra marker beds in the LCRV include the Mount St. Helens set-J/P eruptions (2.5–4.0 ka), set-W/T eruptions (∼AD 1480), and an intermediate-depth tephra, attributed to a Mount St. Helens or Mount Adams eruption (∼1.3 ka). The Late Holocene tephras date the ages of tidal flats and extensive floodplains throughout the length of the LCRV. The Late Holocene marker beds provide the first widespread constraints on wetland sedimentation rates and preservation potentials for archaeology sites in the LCRV.

Gong, Z.; Wang, Z.B.; Stive, M.J.F.; Zhang, C.K., and Chu, A., 2012. Process-based morphodynamic modeling of a schematized mudflat dominated by a long-shore tidal current at the central Jiangsu coast, China.

This paper focuses on the process-based morphodynamic modeling of a mudflat dominated by a long-shore tidal current. The model is schematized as a shore-parallel tidal basin with dimensions similar to the tidal flats near the Wanggang Mouth at the central Jiangsu coast, China. A long-shore tidal current and associated sediment transport are dominant in comparison with their cross-shore components. The mudflat evolution is reproduced for both the case with abundant sediment supply and that with insufficient sediment supply. The simulated flow patterns agree qualitatively with field observations from literature, i.e., involving tidal asymmetry, current directions, and tidal wave features. The analysis of sediment fluxes depicts that deposition occurs from spring tide to neap tide and erosion from neap tide to spring tide. The results show that siltation on intertidal flats is favored by flood dominance, as well as settling and scour lag effects, with less dependence on sediment supply. However, subtidal flats are strongly affected by sediment supply. The simulated double-convex cross-shore profile associated with an abundant sediment supply is qualitatively consistent with field observations. An insufficient sediment supply causes erosion and consequent widening of the subtidal flats. Finally, the practical case with an initial sand seabed is reproduced. The long-shore sediment transport contributes to long-shore variations of cross-shore profiles. Deposition rates increase clearly southward in the area between the lower intertidal and middle subtidal flats when sediment supply is abundant. In contrast, deposition rates increase southward only slightly when sediment supply is insufficient. In addition, stronger sediment supply generates wider intertidal flats. Most importantly, the creek patterns, i.e., the incised creeks on mudflats, are roughly reproduced.

Wang, L.; Xie, Y.; Wu, Y.; Guo, Z.; Xu, Y., and Zhu, X., 2012. Failure mechanism and conservation of the ancient seawall structure along Hangzhou Bay, China.

The ancient seawall along the bank of Hangzhou Bay, which plays an important role in minimizing hazards to people and property along the coastline, has existed for hundreds of years. A recent field survey reveals that there are many hidden problems in the remaining ancient heritage. This work focuses on two points: the failure mechanism of the seawall structure and the ancient mortar prescription for conservation of the seawall, which are investigated through specially designed experiments. The conclusions obtained in this work are of important value for future maintenance of the seawall.

Appendini, C.M.; Salles, P.; Mendoza, E.T.; López, J., and Torres-Freyermuth, A., 2012. Longshore sediment transport on the northern coast of the Yucatan Peninsula.

This paper presents a qualitative assessment of coastal processes along the northern coast of the Yucatan Peninsula based on a method used to estimate the potential longshore sediment transport. Despite the deep-water low-energy wave conditions (Hs  =  1 m) in the study area, erosion is critical in many locations, including the urbanized stretches of coast. The waves were characterized using a 12 y (1997–2009) deep-water wave hindcast data (WAVEWATCH III) as forcing for a spectral wind-wave numerical model (MIKE 21 SW) used to propagate the waves to the coast. Simulated time series of significant wave height, peak period, and direction are compared against in situ measurements at 10 m water depth. Numerical results are further employed for estimation of the nearshore wave climate along the coast. Wave conditions are strongly affected by the wide continental shelf in front of the northern Yucatan Peninsula, with an increase in wave energy at the eastern part of the peninsula where the shelf narrows. The nearshore wave climate is employed for the qualitative assessment of potential longshore sediment transport (LITDRIFT model) in the study area. The sediment transport calculations are consistent with both volume impoundment estimations at a groin and dredging estimates at a harbor (−35,000 m³/y). A net westward potential longshore sediment transport is found along the entire coast, ranging between −20,000 and −80,000 m³/y, except west of Holbox, where longshore transport direction is inverted. Based on sediment transport gradients, potential erosion and deposition areas are identified. Erosion/accretion patterns at nonurbanized areas are consistent with field observations. This dominant westward longshore transport suggests an extremely sensitive shoreline to littoral barriers, as supported by observations in the most urbanized areas. These areas show no gradients on longshore sediment transport, whereas beach erosion is a common feature enhanced by littoral barriers. Shore protection should then be oriented toward sediment management strategies.

En este trabajo se presenta una evaluación cualitativa de los procesos costeros a lo largo de la costa norte de Yucatán, en base a una metodología para la estimación del transporte potencial de sedimentos. A pesar de las condiciones de baja energía de oleaje (Hs  =  1 m) en la zona, los problemas de erosión costera son críticos en varias localidades, incluyendo zonas urbanizadas. Se utilizaron 12 años de datos (1979–2009) de un retroanálisis de oleaje (WAVEWATCH III) como condiciones de frontera para un modelo de oleaje en la zona costera (MIKE 21 SW). Las series de tiempo de altura significante, periodo pico y dirección de oleaje se compararon con mediciones in situ a 10 m de profundidad. Las condiciones de oleaje son muy afectadas por la amplia plataforma continental frente a la costa de Yucatán, mostrando una tendencia a incrementar al acercarnos a la parte este de la península donde la plataforma es reducida. El clima de oleaje determinado a lo largo de la costa fue utilizado para evaluar el transporte potencial de sedimentos (modelo LITDRIFT) en la zona de estudio. Los cálculos de transporte son consistentes con las estimaciones en la zona (−35,000 m³/año). Se determinó una tendencia dominante hacia el oeste para el transporte potencial de sedimentos en prácticamente toda la costa, con valores entre −20,000 y −80,000 m³/año, siendo que únicamente al oeste de Holbox hay una inversión en la dirección del transporte. Los patrones de erosión/acumulación en las zonas no urbanizadas son consistentes con observaciones de campo. La dominancia del transporte de sedimentos con dirección al oeste indica que es un

Tseng, Y.-P.; Huang, Y.-C., and Ditton, R., 2012. Developing a longitudinal perspective on the human dimensions of recreational fisheries.

The purpose of this study is to demonstrate a longitudinal perspective on state-level recreational fisheries that could be used anywhere systematic angler surveys are conducted over time. With six angler surveys from Texas conducted over a 16-year time period, selected human dimension indicators of recreational fishing were analyzed with the index of qualitative variation (IQV) and Spearman rank-order correlation coefficient. Saltwater anglers demonstrated significant upward trends in household income, self-reported skill, preference for catching one particular species, and satisfaction with their fishing experiences. No significant downward trends were found. Although expected in some cases for various reasons, no significant trends were found in gender, baby boomer participation, racial/ethnic differences, years of fishing experience, and average annual days of saltwater fishing. Finally, this paper demonstrates the need for consistent human dimension questions over time in understanding the longitudinal perspective of recreational fisheries.

Bertels, L.; Houthuys, R.; Deronde, B.; Janssens, R.; Verfaillie, E., and Van Lancker, V., 2012. Integration of optical and acoustic remote sensing data over the backshore-foreshore-nearshore continuum: a case study in Ostend (Belgium).

This research addresses the possibilities of the combined use of airborne hyperspectral imaging spectroscopy, airborne laser scanning, and seaborne sonar to study the sediment dynamics in the back-, fore-, and nearshore continuum. In May 2009, airborne light detection and ranging (LiDAR) and hyperspectral data were acquired at low tide of the beach in Ostend, Belgium. In June 2009, seaborne side-scan sonar and single- and multibeam depth and backscatter data were acquired in the nearshore part of the Ostend coastal area at high tide. Both LiDAR and single- and multibeam data were used to create a topographic reference of the back- to nearshore continuum, with an average vertical accuracy of 10 cm. This reference framework was used, in combination with historical data, to study the morphological evolution over the last few years. Hyperspectral data, optionally combined with LiDAR-derived intensity, slope, and elevation data, were used for sedimentological mapping of the back- and foreshore area. Both multibeam backscatter and side-scan sonar data were used to produce a sedimentary surface facies map of the nearshore area. Because no automatic classification of subtle seabed gradients is yet available, the data were manually screened to produce 12 sedimentary classes. Subsequently, the airborne- and seaborne-derived maps were combined to construct an integrated sedimentological and morphological map of the entire area. This was used to interpret and formulate statements about the sediment dynamics of the area.

Boon, J.D., 2012. Evidence of sea level acceleration at U.S. and Canadian tide stations, Atlantic Coast, North America.

Evidence of statistically significant acceleration in sea level rise relative to land is found in a recent analysis of monthly mean sea level (mmsl) at tide stations on the Atlantic coast of North America. Serial trend analysis was used at 11 U.S. Atlantic coast stations and 1 Canadian station (Halifax, Nova Scotia) with record lengths exceeding 75 years to examine change in the linear trend rate of rise over time. Deriving trend estimates that apply in the median year of fixed-length mmsl series, reversals in rate direction (increasing or decreasing) were observed around 1939–40 and again in the mid-1960s except at the northeasternmost stations in the latter period. What has not been observed until recently is a sharp reversal (in 1987) followed by a uniform, near-linear change in rise rate that infers constant acceleration at eight mid- to NE Atlantic tide stations, change not seen at SE U.S. Atlantic stations. Quadratic regression and analysis of variance applied to mmsl series over the last 43 years (1969–2011) confirms that addition of a quadratic term representing acceleration is statistically significant at 16 tide stations from Virginia to Nova Scotia. Previous quadratic model studies have focused on sea level series of longer spanning periods with variable serial trends undermining quadratic expression of either accelerating or decelerating sea level. Although the present 43-year analysis offers no proof that acceleration will be long lived, the rapidity of the nascent serial trend increase within the region of interest is unusual. Assuming constant acceleration exists and continues, the regression model projects mmsl by 2050 varying between 0.2 and 0.9 m above mean sea level (MSL) in the NE region and between −0.3 and 0.4 m above MSL in the SE region.

Nejadkazem, O. and Gharabaghi, A.R.M., 2012. Mathematical model for hydrodynamic behavior of an array of vertical cylindrical piles used as a breakwater. Journal of Coastal Research, 28(6), 1446–1461. Coconut Creek (Florida), ISSN 0749-0208.

A mathematical model is developed to study hydrodynamic behavior of an array of vertical cylindrical piles used as a breakwater (VPB) under irregular waves that impinge normally. The numerical calculation is based on an eigenfunction method and utilizes matched asymptotic boundary conditions. The concept of energy spectra has been used for modeling real hydrodynamic sea wave characteristics, and evanescent modes were considered for each wave component. A new empirical formula for estimation of the contraction coefficient is proposed that includes hydrodynamic wave characteristics in addition to the geometry of a breakwater. The formula models effects of both vena contracta and nonpropagating waves and is advantageous from the prospect of effectiveness and efficiency. Consequently, few evanescent terms are necessary for the eigenfunction expansion method to be confident about the accuracy of results. Results are given for reflection, transmission, and dissipation, and the theoretical value was found to agree quite well with experimental data available in literature. It is concluded that an efficient range of porosity may be located in [0.1, 0.2], and the steeper wave reflects more and transmits less. Also, in shallow and intermediate water depth, the VPB operates optimally and dissipates the energy of waves effectively. The VPB is recommended for significant wave periods of more than 2.0 seconds and performs better for a wave steepness of less than 0.025.

Dawson, A.G.; Gómez, C.; Ritchie, W.; Batstone, C.; Lawless, M.; Rowan, J.S.; Dawson, S.; Mcilveny, J.; Bates, R., and Muir, D., 2012. Barrier island geomorphology, hydrodynamic modelling, and historical shoreline changes: an example from South Uist and Benbecula, Scottish Outer Hebrides.

A partly quantitative reconstruction is provided of the evolution of Gualan Island, a barrier island located between South Uist and Benbecula in the Scottish Outer Hebrides, using historical maps, aerial photographs, and Lidar (light detection and ranging) data. Geomorphological changes over the last approximately 200 years are described together with quantitative changes in the dimension of the barrier island, including rates of shoreline retreat. A series of digital terrain models (DTMs) provided the boundary conditions for a two-dimensional (2D) ocean circulation tide-surge model simulating water level and wave conditions associated with a highly destructive storm that took place during January 2005. During this storm event, the central part of the barrier island was overtopped by waves. Validating the hydrodynamic model against eye-witness and field evidence obtained after the 2005 storm allowed simulation of a range of potential future breaching scenarios. Thus with the same storm conditions a large barrier breach 500 m wide would result in wave heights rising by 0.8–0.9 m on hitherto sheltered shorelines.

Thorne, K.M.; Takekawa, J.Y., and Elliott-Fisk, D.L., 2012. Ecological effects of climate change on salt marsh wildlife: A case study from a highly urbanized estuary.

Coastal areas are high-risk zones subject to the impacts of global climate change, with significant increases in the frequencies of extreme weather and storm events, and sea-level rise forecast by 2100. These physical processes are expected to alter estuaries, resulting in loss of intertidal wetlands and their component wildlife species. In particular, impacts to salt marshes and their wildlife will vary both temporally and spatially and may be irreversible and severe. Synergistic effects caused by combining stressors with anthropogenic land-use patterns could create areas of significant biodiversity loss and extinction, especially in urbanized estuaries that are already heavily degraded. In this paper, we discuss current ideas, challenges, and concerns regarding the maintenance of salt marshes and their resident wildlife in light of future climate conditions. We suggest that many salt marsh habitats are already impaired and are located where upslope transgression is restricted, resulting in reduction and loss of these habitats in the future. In addition, we conclude that increased inundation frequency and water depth will have negative impacts on the demography of small or isolated wildlife meta-populations as well as their community interactions. We illustrate our points with a case study on the Pacific Coast of North America at San Pablo Bay National Wildlife Refuge in California, an area that supports endangered wildlife species reliant on salt marshes for all aspects of their life histories.

Roig-Munar, F.X.; Martín-Prieto, J.A.; Rodríguez-Perea, A.; Pons, G.X.; Gelabert, B., and Mir-Gual, M., 2012. Risk assessment of beach-dune system erosion: beach management impacts on the Balearic Islands.

The beach–dune system is a sedimentary environment that is fragile and dynamic. Any change to it can have potential adverse effects on its stability. In recent decades, this environment has been heavily exploited for recreation with management practices that do not have enough consideration of protective and aesthetic values. As a result, erosion has increased—mainly in the foredunes—and upset the balance of the beach–dune system. The assessment of the morphoecological conservation state plays a major role in forecasting natural hazard impacts. This paper correlates the most frequented sectors with the most eroded parts in four beach–dune systems of the Balearic Islands (two in Majorca and two in Minorca) through the Digital Shoreline Analysis System. The four beaches show that the coastline retreats at locations with the highest attendance. Two situations may arise as a function of the management practices employed: (1) the beach and foredune area is eroded or (2) the beach–dune system recovers. The paper also describes appropriate beach and foredune management practices that allow recovery of a system degraded by human activity. We compare these practices with strategies adopted at beaches solely for commercial gain in the Balearic Islands. A space–time evolution, from 1956 to 2008, of 78 beaches of the Balearic Islands was carried out through multivariate analysis of a checklist of beach–dune features and management measures. The results show that beach–dune management based on geomorphological criteria improves conservation of the natural system and minimises risk of erosion. Recovery of vegetation is also encouraged.

El sistema playa–duna constituye un medio sedimentario frágil y dinámico. Cualquier pequeño cambio puede tener efectos significativos sobre su estabilidad. En las últimas décadas, este entorno ha sido muy explotado con fines turísticos. Consecuentemente la erosión se ha incrementado, principalmente en la zona de dunas delanteras (“foredunes”), perturbando la estabilidad de todo el sistema playa–duna. La capacidad de adaptación de este entorno está relacionada con su estado de conservación. La evaluación del estado de conservación morfoecológico es importante para predecir el impacto de amenazas naturales. La primera parte del artículo muestra la correlación existente entre los sectores más frecuentados y las partes más erosivas en cuatro sistemas playa–duna de las Islas Baleares (dos en Mallorca y dos en Menorca), a través de un sistema de análisis digital del litoral. Las cuatro playas muestran una retirada de la costa donde se encuentra la urbanización, pero dependiendo de las técnicas de gestión, la erosión se concentra en la playa y en la zona de “foredunes” o bien pueden desencadenar la recuperación del sistema playa–duna. La segunda parte del artículo muestra las medidas de gestión adecuadas para la playa y la “foredune” que permitan la recuperación de todo el sistema. Comparamos estas medidas orientadas a la recuperación de los impactos antrópicos con otras medidas que se han aplicado a varias playas de las Islas Baleares, únicamente guiadas por sus fines comerciales. Por último se muestra la evolución espacio–tiempo, de 1956 a 2008, de 78 playas de las Islas Baleares a través de un análisis multivariado de una lista de las características del sistema playa–duna y de las medidas de gestión. Los resultados muestran que la gestión basada en criterios geomorfológicos mejora la conservación del sistema natural y por lo tanto, minimiza el riesgo de erosión. La recuperación de la vegetación también se ve favorecida.

Rao, X.; Li, L.; Amini, F., and Tang, H., 2012. Smoothed particle hydrodynamics modeling of combined wave and surge overtopping and hydraulic erosion of an articulated concrete block-strengthened levee system.

Combined wave and surge overtopping may cause damage on earthen levees. Levee strengthened on the levee crest and landward-side slope can provide protection against the erosion damage induced by the combined wave and surge overtopping. In this paper combined wave overtopping and storm surge overflow of a levee with a trapezoidal cross section strengthened by an articulated concrete block (ACB) system was studied in a purely Lagrangian and meshless approach, two-dimensional smoothed particle hydrodynamics (SPH) model. By comparing with the results of full-scale experiment data, the model was verified, and the erosion parameters were calibrated. Time series of overtopping discharge and flow thickness at six locations on the levee crest and landward-side slope were calculated. New equations were developed for average overtopping discharge, mean flow thickness, root mean square (RMS) wave height, mean velocity, and velocity of the wave front down the landward-side slope. The shear stresses on the levee crest and landward-side slope were calculated. The characteristics of soil loss were given. Equations were also provided to estimate soil loss. The range of the application of these equations was discussed.

Schwartz, R.K., 2012. Bedform, texture, and longshore bar development in response to combined storm wave and current dynamics in a nearshore helical flow system.

Fluid motion, bedform, and textural data were collected across the eastern Lake Michigan nearshore zone during a typical coastal storm event. The profile included four stable longshore bars (designated 1–4 lakeward) and extended 400 m offshore to a depth of about 6 m. The storm-forced flow system included three major components: incident-wave oscillatory flow, a wind-forced coastal current, and a breaking wave–associated longshore current. Widespread change across the profile included (1) maximum wave height (Hs ∼1.27 m; T  =  3.5–4.0 s) near bar 3, where the largest waves broke, followed by smaller waves over bar 2 and slightly increased wave height over bar 1; (2) maximum orbital velocities (Um > 37–56 cm/sec) over bars 4 and 3 and lower values over the inner bars; (3) maximum shore-parallel, wind-driven current speed near bar 4 (43 cm/s maximum) decreasing landward to near bar 2 (∼17 cm/s maximum) followed by increased longshore current speed landward of bar 2 (∼19 cm/s); (4) three-dimensional ripples, including hummocks and longitudinal forms, along the outer profile to a dominance of two-dimensional wave ripples along the inner profile; and (5) slight landward coarsening of bar crest sand and strong lakeward coarsening of trough sand. The combined flow at all locations was net shore-parallel becoming stronger and increasingly unimodal along the outer profile. Distinct second-order patterns within the widespread trends were associated with bar and trough bathymetry. Orbital velocity increased toward bar crests, whereas current velocity increased and/or became far dominant along trough axes. Slight textural coarsening extended from bar flanks toward crests, whereas a relatively strong gradient of textural coarsening occurred from bar flanks into troughs. Two-dimensional wave ripples and flat bed/postvortex ripple zones typified the upper parts of middle to inner bars, whereas current-dominated three-dimensional and longitudinal ripple forms dominated the middle to outer troughs. The combined data sets indicate that shore-parallel zones of weak secondary helical flow result in divergent transport away from trough axes and convergent transport toward bar crests. Strong storm-forced currents with helical secondary motion are hypothesized to form and maintain the longshore bar system, as well as linear shoreface bars in general, whereby the bars and troughs are depositional and erosional forms, respectively. The cumulative effect of multiple storms causes the degree of downward scour, bar dimensions, and trough coarsening to increase lakeward across the profile. The Great Lakes' bars are stable passive features during intervening transport-inefficient fair-weather conditions. The storm-transport model is one in which net transport along the entire shoreface is shore parallel with maximum alongshore sediment transport in middle to outer profile positions.

Stammermann, R. and Piasecki, M., 2012. Influence of sediment availability, vegetation, and sea level rise on the development of tidal marshes in the Delaware Bay: a review.

The ecological value of tidal marsh systems for the environment and their adjacent water body is increasingly recognized. Natural and anthropogenic changes in the environment represent challenges to the development and sustainability of marsh systems that can lead to degradation and losses when negative impacts accumulate. Physical, chemical, and biological processes in marshes are complex, highly intertwined, and still not entirely understood. A better understanding is essential for the management of marshes and the assessment of impacts caused by future changes. This paper presents a review of tidal marshes in general and the problems they are facing with a special emphasis on the Delaware Estuary. The number of factors affecting tidal marshes is large, and a review of all would go beyond the scope of this paper. In this respect, three major influencing parameters are examined more closely: sediment transport, sea level rise, and vegetation. Furthermore, research approaches for these parameters, ranging from field measurements to numerical modeling, are examined, including an overview of studies that have been conducted in the Delaware Estuary. The review showed that the Delaware Bay is an active area for tidal marsh research, with many projects focusing on ecological field studies, restoration efforts, sediment inventories, and the long-term accretion of tidal marshes. Numerical modeling was primarily used for hydrodynamic studies in the pelagic zone, but only few studies exist that model marsh processes in a high spatial and temporal resolution.

Bernatchez, P., and Fraser, C., 2012. Evolution of coastal defence structures and consequences for beach width trends, Québec, Canada.

Over recent decades, amplification of coastal erosion, coupled with the expansion of the built environment in Québec's maritime region, has led to a significant increase in defence structures. On unconsolidated coasts, severe beach width reduction was noted following the construction of hard engineered structures when compared to beaches with no such constructions. Beaches in the sectors of Sept-Îles and Percé, where shorelines have been modified by rigid defence structures parallel to the coast, have had a reduction in width of 85% and 44%, respectively. In some places, beaches have almost completely disappeared. On low-lying sandy coasts, although an immediate width reduction of 19% to 27% is attributable to the encroachment of the structures on the upper beach, most of the width reduction (74% to 81%) is due to erosion caused by the reflective nature of the defence structures. The effects of the defence structures on the sediment deficit of the beaches are much worse for coasts with a high level of sediment transit. Such consequences significantly diminish coastal resilience to climate change and storm events because, under such circumstances, beaches cannot absorb nearly as effectively the energy of storm waves. A look at the historical record of coastal construction shows that rigid defence structures parallel to the coast have not only led to beach erosion, but they have also limited the shoreline progradation process. The sediment budget variations of beaches on natural coasts correlate well with relative sea-level trends. An average decrease in beach width of 43% due to sea-level rise was measured on natural coasts. However, the results show that the reaction of a beach to an increase in sea level is much more complex than a simple translation of its equilibrium profile. Beach width is a very good geomorphological indicator for evaluating long-term trends with respect to the sediment budget of coastal systems, as well as evaluating the relative importance of natural and anthropogenic causes of the sediment deficit of beaches.

L'amplification de l'érosion côtière jumelée à l'accroissement du cadre bâti au Québec maritime a engendré une augmentation importante des structures de protection durant les dernières décennies. Les ouvrages de protection rigides ont entraîné une réduction de la largeur des plages sur les côtes meubles comparativement aux plages naturelles sans artificialité. Les plages dont la ligne de rivage est artificialisée par une structure rigide de protection ont connu une réduction de leur largeur de 85% et de 44% respectivement pour les régions de Sept-Îles et de Percé. La plage a presque complètement disparu à certains endroits. Sur les côtes basses sablonneuses, la réduction totale de la largeur des plages est attribuable à une réduction instantanée de 19 à 27% par l'empiétement des ouvrages sur le haut de plage, mais surtout à l'érosion (74% à 81%) en raison de la nature réflective des ouvrages de protection. Les effets des ouvrages de protection sur le déficit sédimentaire des plages sont beaucoup plus néfastes pour les côtes avec un fort transit sédimentaire. Ces conséquences diminuent de manière significative la résilience côtière aux changements climatiques et aux événements de tempête puisque les plages ne peuvent plus absorber de manière aussi efficace l'énergie des vagues de tempête. Le bilan de l'évolution de l'artificialité de la côte indique que les structures rigides de protection ont eu pour conséquence non seulement de provoquer une érosion des plages, mais aussi de limiter le processus de progradation de la côte. Une variabilité dans le bilan sédimentaire des plages sur des côtes naturelles a aussi été mesurée en fonction de la tendance du niveau marin relatif. Une diminution d'une moyenne de

Chaaban, F.; Darwishe, H.; Battiau-Queney, Y.; Louche, B.; Masson, E.; El Khattabi, J., and Carlier, E., 2012. Using ArcGIS® Modelbuilder and aerial photographs to measure coastline retreat and advance: North of France.

Coastal areas are naturally dynamic with changes occurring over periods of time. When the shoreline moves landward, coastal erosion becomes a serious problem, and the rate of change has to be calculated. Coastline retreat is one of the best indicators of coastal erosion. Here, the geographic information systems (GIS) platform (ArcGIS® 9.3.1; Esri software) is used to study the long-term (last 59 years) shoreline change in the area of Hardelot-Plage and Sainte Cécile–Plage (a north–south 14-km-long beach), in northern France. The primary aim of this study was to develop a methodology for calculating shoreline change using ArcGIS Modelbuilder and aerial photographs. Changes in 14 coastlines over the course of 59 years (from 1946 to 2005) were digitized and represented in ArcGIS 9.3.1 platform. Two hundred and ninety-two transects perpendicular to the shoreline were used to estimate coastal erosion and deduce the recession rate.

The Modelbuilders (two models) created and used in this work are generic models that can be used for geoprocessing linear features. One model can be used to ascertain the intersection between linear features (transects and shorelines), adding a new field to the attribute table and calculating the geometry of the intersection points. A second model can be used to add a new field to the attribute table and calculate the distance on the transect lines between the linear reference feature and other linear features, in this study between the baseline (established adjacent to the series of shoreline positions) and the shoreline. The results show that the shoreline change rates between 1947 and 2005 along the Hardelot and Sainte Cécile coasts are generally negative; 82.2% of transects have values less than zero (i.e., retreat) and outside of the error margin (±10 m). Nevertheless the shoreline change shows successive phases of advance and retreat over the same period.

Traini, C.; Schrottke, K.; Stattegger, K.; Dominguez, J.M.L.; Kacenelenbogen Guimarães, J.; Vital, H.; D'avila Beserra, D., and Aquino da silva, A.G., 2012. Morphology of subaqueous dunes at the mouth of the dammed river São Francisco (Brazil).

Economic development of the São Francisco River basin has increased by building seven river dams since the 1950s. Subsequently, strong coastal erosion reaching maximum rates of 98.6 m/year has been recorded at the river mouth, also leading to the destruction of a coastal village. This work combines discharge data with new sediment and hydro-acoustic records, collected in January 2009, to verify the impact of river damming on processes, controlling coastline evolution. Data analysis is focused on discharge evolution, morphology and sediment composition of subaqueous dunes as well as on the impact by tidal currents. Discharge has been strongly regulated since 1986, when the last river dam was implemented. Again, bedform morphology seems to be not affected neither by reduced river-discharge nor by reduced sediment supply. However, migration rates of these dunes, as calculated, are lower due to decreased discharge. At the same time, tidal impact is strengthened at the lowermost part of the river. From this we assume, that the replenishment of sediment at the coast near the river-mouth might be time-delayed, which could support coastal erosion.

Le développement économique du bassin versant du fleuve São Francisco a été favorisé par la construction de sept barrages hydroélectriques sur le cours du fleuve. Par suite, une forte érosion du trait de côte atteignant un taux maximal de 98,6 m par an a été enregistré à l'embouchure du fleuve, conduisant à la destruction d'un village côtier. Ce travail allie des données de débit, de prélèvements sédimentaires et de nouveaux enregistrements hydroacoustiques collectés en janvier 2009 pour vérifier l'impact d'un barrage sur les processus contrôlant l'évolution du trait de côte. L'analyse des données est concentrée sur l'évolution des débits fluviatiles, la morphologie et la granulométrie du sédiment composant les dunes du fond du fleuve ainsi que l'impact des courants de marée. Les débits fluviatiles ont été fortement régulés depuis 1986 alors que la construction du dernier barrage débutait. La morphologie des dunes fluviatiles ne semble pas être affectée par la rétention sédimentaire des barrages. Cependant, les taux de migration calculés de ces dunes sont plus faibles en raison de l'affaiblissement des débits. Dans le même temps, l'impact de la marée s'est renforcé dans la portion la plus distale du delta. Nous présumons ainsi que l'alimentation sédimentaire du littoral à proximité de l'embouchure fluviale est retardée et donc contribue à l'érosion de cette portion du littoral.

Elekema, M.; Wang, Z.B., and Stive, M.J.F., 2012. Impact of back-barrier dams on the development of the ebb-tidal delta of the Eastern Scheldt.

The Eastern Scheldt tidal basin in the SW part of the Netherlands has seen dramatic changes due to human intervention in the past few decades. The construction of two back-barrier dams in 1965 and 1969 had a significant impact on tidal hydrodynamics and sediment transport. The effects of these interventions were still ongoing when the hydrodynamic regime was altered again by the construction of the storm surge barrier between 1983 and 1986.

This research describes the hydrodynamic and morphological evolution of the Eastern Scheldt ebb-tidal delta between 1960 and 1983, before construction of the storm surge barrier started. The analysis focuses on how the back-barrier dams changed the tidal flow on the ebb-tidal delta and how these altered hydrodynamics influenced sediment transport and morphology. It starts with a description of the observed hydrodynamic and bathymetric changes. These observations are used as input for a process-based numerical model (Delft3D FLOW), which is used to simulate situations before and after channel closures.

In the decades before 1965, the Eastern Scheldt exported large quantities of sediment towards the sea through its inlet. The implementation of the dams caused a significant increase in tidal prism, which was observable in the response of the bathymetry; the export and the rates of channel deepening and ebb-tidal delta growth both increased. Analysis of tidal-flow measurements and model output show a persistent trend for sediment transport towards and out of the Eastern Scheldt inlet. The construction of the back-barrier dams only amplified this export by increasing the tidal prism and pushing the basin out of equilibrium even more than it apparently already was.

Marriner, N.; Pirazzoli, P.A.; Fontugne, M.; Geérout, M.; Guillaume, M.M.M., and Reyss, J.L., 2012. A geomorphological reconnaissance of Tromelin Island, Indian Ocean.

Tromelin is a small coral reef island (∼1 km²) located in the Indian Ocean, approximately 440 km E of Madagascar and 580 km N of La Réunion. Despite the presence of a permanent Météo France weather station on Tromelin since the 1950s, a detailed geomorphological study of the island has never been undertaken. In this paper, we describe the geomorphology of the atoll, detailing seven geomorphological zones from the outer reef to the atoll crown. We also discuss Holocene relative sea-level changes in the light of new radiometric datings. Uranium–thorium dating of a remnant mid-Holocene reef-flat yielded an age of 5700 ± 400 years and could be interpreted as a relative sea level approximately 1.2 m above present. Subsequent possible sea-level positions have been inferred from coral conglomerates left by high-energy waves. These conglomerates might be interpreted as a beachrock, cemented mainly in the former intertidal zone when sea level was still approximately 1.2 m above present. The radiocarbon dating of three coral fragment samples collected from these conglomerates has yielded ages spanning 4200 to 2900 calibrated years BP.

Ferrer García, C., and Blázquez Morilla, A.M., 2012. The evolution of the Albufereta Lagoon (Western Mediterranean): Climate cycles and sea-level changes.

The results from analyses of cores and pits carried out during two research campaigns in the littoral lagoon of Albufereta d'Alacant (Western Mediterranean) shed light on the sedimentary dynamics of this area. The erosive sequence and stages recorded in periods prior to the Middle Holocene bear witness to the environmental changes that occurred in the littoral zone between isotope stages 2 and 1 in relation to the rise in sea level during the Holocene. As the rise in the sea level slowed, a freshwater lagoon environment formed around 4000 YBP. After that time, the changes in the littoral environment became less pronounced and were caused by atmospheric circulation in the Northern Hemisphere. Around 3000 YBP, a lagoon open to the sea emerged as the result of a relative change in the sea level. This environment lasted approximately until 1500 YBP. The prolonged survival of the lagoon created by this event and the increase in the marine influence during the later stages of the lagoon's development may be connected with human management of the environment in the Roman era. It was followed by a restricted lagoon environment characterized by cyclical changes in the environment lasting hundreds of years.

Pereira, L.C.C.; Pinto, K.S.T.; Da Costa, K.G.; Vila-concejo, A., and Da Costa, R.M., 2012. Oceanographic conditions and human factors on the water quality at an Amazon macrotidal beach.

Atalaia beach is situated in the NE of the Brazilian state of Pará and is one of the most popular with tourists and local beachgoers. This paper describes the seasonal variation in the meteorologic and oceanographic characteristics of the study area, as well as the effects of the lack of a public sanitation system on the quality of the water used by beachgoers. Oceanographic campaigns were carried out between November 2008 and September 2009. The study area is characterized by high rainfall rates (>1900 mm during the rainy season), NE winds with mean speeds of up to 4.36 m/s in the dry season and 3.06 m/s in rainy season, macrotidal conditions (tidal range >4.0 m), moderate tidal current speeds (up to 0.5 m/s), and significant wave heights up to 1.5 m. Water temperature was relatively homogeneous (27.6°C to 29.3°C). Salinity varied from 5.7 (June) to 37.4 psu (November). The water was well oxygenated (up to 9.17 mg/L), turbid (up to 118 nephelometric turbidity units), alkaline (up to 8.68), and eutrophic (maximum of 2.36 µmol/L for nitrite, 24.34 µmol/L for nitrate, 0.6 µmol/L for phosphate, and 329.7 µmol/L for silicate), and it presented high concentrations of chlorophyll a (up to 82 mg/m³). The natural conditions observed in the present study indicate the need for a review of the hydrologic criteria used for the evaluation of beaches by national and international agencies and their adaptation to the reality of the Amazon Coast. The lack of a public sanitation system has led to bacteriologic contamination and the loss of water quality.

A praia de Atalaia está situada no nordeste do estado do Pará (Brasil), e é uma das mais turísticas e populares praias do litoral amazônico. O objetivo deste trabalho foi descrever as variações sazonais das condições meteorológicas e oceanográficas da área estudada, bem como conhecer os efeitos da falta de um sistema público de saneamento básico sobre a qualidade da água utilizada para banho pelos usuários desta praia. Campanhas oceanográficas foram realizadas entre novembro de 2008 e setembro de 2009 e dados meteorológicos foram fornecidos pelo Instituto Nacional de Meteorologia. Os resultados mostraram que a área de estudo é caracterizada por possuir altas precipitações (>1900 mm durante o período chuvoso), ventos de nordeste com velocidades médias de até 4,36 m/s no período seco e 3,06 m/s no período chuvoso, macromarés com alturas acima de 4,0 m, correntes de marés com velocidades médias de até 0.5 m/s, e altura de ondas significantes de até 1,5 m. A temperatura da água foi relativamente homogênea (27,6 a 29,3°C). A salinidade variou de 5,7 (junho) a 37,4 psu (novembro). A água foi bem oxigenada (até 9,17 mg/L), turva (até 118 NTU), alcalina (até 8.68), eutrófica (máximo de 2,36 µmol/L para nitrito, 24,34 µmol/L para nitrato, 0,6 µmol/L para fosfato e 329,7 µmol/L para silicato), e apresentou altas concentrações de clorofila a (até 82 mg/m³). As condições naturais observadas no presente estudo indicam a necessidade da revisão dos critérios de qualidade da água das praias amazônicas, estabelecidos por agencias nacionais e internacionais. Por outro lado, a falta de um sistema público de saneamento tem causado contaminação bacteriológica e comprometido a qualidade da água da praia de Atalaia.

Alberico, I.; Amato, V.; Aucelli, P.P.C.; D'Argenio, B.; Di Paola, G.; and Pappone, G., 2012. Historical shoreline change of the Sele Plain (southern Italy): the 1870–2009 time window.

In the Mediterranean, the coastal population was estimated at 146 million in 1990 and the urban coastal population alone is projected to rise to 176 million by 2025, with an addition of 350 million of tourists per year. In coastal zones, forecasting shoreline location and changes in time is a basic tool for decisional making regarding land management and future planning. Historical maps, aerial photography, topographic maps and a beach survey were used as data sources to detect the shorelines of the Sele Plain coastline between the towns of Salerno and Agropoli (southern Italy) and define its change from 1870 to 2009. By using the potential of ArcGIS release 8.3 software and its extension digital shoreline analysis system, we followed two main stages. The first required identification of the shorelines, reducing to a minimum the errors associated to the suitability of source material, distortion of the photographs, residuals in georeferencing, and seasonal shoreline variation. The second was to define the shoreline variations along 170 transects spaced every 200 m. This systematic analysis showed that in the Sele River plain the highest rates of erosion, generally localized at river mouths (Picentino River, mean value  =  0.4 m/y; Sele River, mean value  =  1.3 m/y), have decreased in the last 20 years, revealing that the beach system is acquiring new coastal stability.

Cheong, S., 2012. Fishing and tourism impacts in the aftermath of the Hebei-Spirit oil spill.

On December 7, 2007, the Hebei-Spirit oil spill poured 10,900 tons of light crude oil into the waters off the Yellow Sea of the Republic of Korea following a collision between a Samsung Heavy Industries crane barge and the Hebei-Spirit oil tanker (KORDI Staff, 2008; Hebei-Spirit Oil Spill cleanup; Korea Ocean and Research Development Institute, 48p). The Hebei-Spirit oil spill was the largest spill in Korean history, and it dramatically affected the fishing and tourism communities of the Taean region in Choognam Province. Typically, oil spills cause considerable damage to the fishing and tourism industries because of those industries' dependence on natural coastal resources. Though fishing and tourism are affected by the spill simultaneously, their distinct resource uses, industry characteristics, and culture lead to different reactions and outcomes.

Theuerkauf and Rodriguez (2012) utilized terrestrial laser scanning data obtained at Onslow Beach, North Carolina to create digital elevation models and quantify volumetric beach change; and compared their results with data derived from traditional beach profiling. The authors conclude full coverage datasets such as those obtained by terrestrial laser scanning and LIDAR can be used to more accurately quantify volume change, and furthermore are superior to the profile method when measuring storm response, coordinating research and engineering projects, and for other coastal management endeavors. However the inability to capture the dune and offshore environments by these methods is identified as a major shortcoming of the article and the terrestrial laser scanning technique utilized by Theuerkauf and Rodriguez (2012) is further compromised by survey accuracy repeatability issues, and constant on-the-fly changing of the survey boundaries to capture small-scale geomorphic features over large areas of the beach. This conversely augments the value of beach profiling as a suitable method for describing short- and long-term changes over expansive stretches of shoreline such as Bogue Banks, North Carolina for research and coastal management activities.